Vacuum gravity press



June 1952 v. E. HEYWOOD VACUUM GRAVITY PRESS Filed Dec. 21, 1946 J Q IE: 7A D D c E I Q E n. 1 7 6 Z 5 w ll v 8 A u mm m ggfiw !W/IIEI :EEEFLJA 5 a m. i v 5 b (I. w mum [is 6 7, m; Q L L a C Patented June 10, 1952 VACUUM GRAVITY PRES S Vincent E. Heywood, Worcester, Mass lassignor to United States Envelope-Company, Springfield, Mass., a corporation of Maine Application December 21, 1946, Serial No. 717,749

7 Claims. 1

This invention relates in general to presses, and more particularly to a type of small press that is adapted, among other things, for use in the manufacture of various paper and cardboard articles, to clamp and hold in firm contact the adhesivecoated layers or areas of such articles while the moist adhesive is setting or drying.

Heretofore, it has been the practice in factories specializing in the production of such articles, to use for this purpose a small press in which the movable or pressure-applying member is connected to the piston of a double-acting cylinder and piston unit, having suitable means for admitting compressed air, alternately, to opposite ends of the cylinder, in order to move the pressure-applying element into work-contacting position and then, after the glue has dried, into work-releasing position, to permit introduction to the press of other work to be acted upon. Such a device requires a stuffing box for the piston rod, and complicated valving for the motive fluid.

According to my invention, as hereinafter described, a single acting piston and cylinder unit is employed, thus eliminating the usual stufiingbox. In my improved press, gravity is utilized to obtain the operative or work-contacting stroke of the pressure-applying element, while the opposite or work-releasing stroke is obtained by suction or vacuum. This results in more economical operation of the press, as well as in a less complicated and less expensive construction. Furthermore, my invention, as hereinafter described, enables the impact of the pressure-applying element upon the work to be advantageously lightened, so as to avoid any damage to the work, or any disturbance or displacement of its adhesivecoated parts. In addition, said pressure-applying element has its weight augmented by the relative- 1y heavy cylinder of said piston and cylinder unit, thereby to provide the optimum conditions .for holding and clamping the work after said element has moved into contact therewith.

Other and further objects and advantages of my invention will be made apparent by the following detailed description thereof, taken in connection with the accompanying drawings in which Fig. 1 is a front view, partly in section, showing the improved clamping press of my invention, with its pressure-applying element in raised or work-releasing position.

Fig. 2 is a sectional view of said press, at right angles to Fig. 1, showing .the pressureapplying element in lowered or work-contacting position.

Fig. 3; is a fragmentary view, partly. in section,

. 2 showing a treadle-operated valve by which the press operation is controlled.

Like reference characters refer to like parts in the difierent figures,

' The stationary .bed or platen of my improved clamping press is provided by a horizontal, preferably rectangular, member I of suitable material, adapted to rest fiat on a bench or table A at which the operator works. Suitably secured to member I, crosswise of each end thereof, are two spacedapart standards or uprights 2, 2, which are preferably connected and made relatively rigid by a suitable brace 3. At their upper ends the uprights 2, 2 are formed with matching arcuatebottomed slots 4, 4 to receive and confine the ends of a shaft 5, extending horizontally across the space between said uprights and prevented from becoming displaced endwise by any suitable means such as surrounding collars 6, 6 held by set-screws 'I, I in abutting relation to the respective opposed faces of said uprights.

The shaft 5 thus rockably mounted in the standards 2, 2 carries at its central portion a depending arm 8 here shown as held in position by a set screw 9. The arm 8 is formed with a threaded bore It), extending at right angles to the shaft 5 and receiving a threaded rod II, which constitutes in efiect an adjustable extension of the arm 8. That is to say, the rod II is arranged to be screwed in or out in the bore III by means of a nut I2, which is stationarily held on said rod by a pin I3, the turning of the rod serving to increase or decrease as the case may be the, downward projection of the rods lower end beyond the arm 8; when the desired adjustment has been made, the rod is locked in adjusted position by means of a nut I4 which is screwed upwardly on the rod into firm engagement with the lower end of arm 8.

The lower end of the rod II carries a relatively stationary piston I5, whose means of connection to the rod is preferably of swivel character, to permit said piston to be self-aligning relative to a movable cylinder I6 with which said piston is operatively associated, as hereinafter described. The piston I5 is of single-acting type, with its open end or skirt extending upwardly around the rod II; for purposes of such self-aligning action, the pistons connection to the rod is by means of an interior plate I! which has a central aperture I8 loosely surrounding the rod II above the latters'terminal enlargement I9. The enlargement I9 has an upper surface 20 of convex spherical contour, for cooperation with a surface ll of concave spherical contour provided by the underside of plate il in concentric relation to the rod aperture l8 thereof. The ends of plate I! are secured by bolts 22, 22 to diametrically opposite interior shoulder portions 23, 23 or the piston (5.

The cylinder 18 is of single-acting type, its upper end being open for passage of the rod H and its lower end being closed by a preferably integral head 24. The head 24 is extended laterally to provide an annular flange 25 which serves for the passage of a series of bolts 25, 26 (only one being shown) by which a fiat pressure-applying member 27 is attached to said cylinder head 24; Said member 21 is here shown as rectangular in shape, to correspond with the bed or platen i; its end portions as shown in Fig. 2 have a slight spacing or clearance relative to wear plates 28, 28 secured to the inside surfaces of the uprights 2, 2. The member 2'! carries on its under surface a pad 29 of rubber, felt or the like, in opposed relation to a similar pad 30, secured to the upper surface of the stationary bed or platen l. The cylinder head 24 is interiorly recessed, as shown at 3!, and communicating with this recess is a threaded passage 32 into which is screwed a fitting 33 that is connected by flexible tubing 34 to a fitting 35, Fig. 3, that is screwed into a port or passage 38 communicating with the bore 31 of a valve body 38.

Said valve body 38 is here shown as secured in any suitable Way to the underside of the bench or table A, and its bore 31 containsa slidable valve member, that includes as shown in Fig. 3-, a lower piston portion 39, an upper piston portion M3 and a short intermediate reduced diameter portion ii. Projecting from upper piston portion 40 is 'a lug 42, adapted by contact with the upper or closed end of bore 31 to maintain in said bore a space 33 with which communicates a port or passage as that has a pipe connection to any suit= able source of suction or vacuum, not shown. Such suction or vacuum is thus always effective in the space :33, and tends normally to hold the valve member at the upper limit of its travel, in the position shown. by Fig. 3, corresponding to the press position shown by Fig. 2'.

The valves lower piston portion 39. has a. downward projection 66, to which is pivotally connected at M a link orrod 48 whose lower end is pivotally connected at 49 to a treadle 50, located conveniently for foot operation by the operator of the press. valve downwardly, and carries piston portion Ml below the port or passage 36; this makes the suction eiiective through passage 36, tubing 36 and fitting 83 in the cylinder space 5! (Fig. 2) with the result that the cylinder 16 and its at tached member 2! are drawn upwardly to the position shown by Fig. 1, the parts being held by the suction in this position so long as the treadle Si} is held down by the operators foot. This gives opportunity for the removal of work that has been in the press and for the disposal of one or more pieces of unpressed work on the platen pad 3o. Then upon removal of foot pressure from treadle 50, the valve is immediately drawn up by the suction to the position shown in Fig. 3, cutting off the suction to the press, and registering with passage 36 the annular space that surrounds the reduced diameter valve portion 4!.

The said annular space around valve portion ii is in communication with the atmosphere by way of a restricted bleed passage 52 through the lower piston portion 39 of the valve. Thus, as soon as the valve arrives at the position shown in Fig; 3, air begins to new in a limited quantity through bleed passage 52 and tubing. to the Depression of treadle pulls the cylinder space 5 l, gradually relieving the vacuum that previously had held up the cylinder [6 and plate 21 in the position shown by Fig. 1, and permitting said last-named parts to descend, by their own weight, toward the work on platen pad 30. This descent of the pressure-applying parts is at a substantially uniform rate, which can be made as slow and gradual as desired (by properly proportioning the bleed passage 52) so as to avoid all possibility of damage to the work, or disturbance of the registry of its adhesive-coated parts, by undue impact from the descending parts. The latters pressure on the work is always substantially uniform, being the pressure produced by the combined weights of the cylinder l6 and attached plate 27.

These pressure-applying parts are guided in their downward and upward movements by the contact of the cylinders interior wall with the relatively-stationary piston l5. While the piston 15 thus serves to guide the pressure elements in avertical path, the mounting of said piston is so arranged as to permit the parts to assume in their operative position (Fig. 2) an out-of-level relation on account of the interposed thickness of the work, this compensation of position being permitted not only by the trunnion mounting of the shaft 5-, but also by the capacity for limited swiveling movement in any direction afforded by the surfaces 26 and 2! of the connection between said piston and the rod H. work has sustained the weight of cylinder l6 and pressure plate 2'! for an adequate time, to permit the adhesive to set and dry, the operator, by depression of treadle 56, again makes the vacuum eiiective in the cylinder space 5! to raise the cylinder and pressure plate to the position shown in, Fig. 1, so that the finished work can be replaced by other work that needs to be subjected to pressure. For adapting the press to work of various different thicknesses, the turning of rod H in the arm 8, to change the position of piston 15-, provides an adjustment of the height to which the pressure plate 2! will rise, at each operation of the press.

I claim:

1. A press of the class described comprising a stationary bed or platen, an opposed movable pressure-applying element, a single-acting cyl inder attached at its head end to said element, a relatively-stationary piston in said cylinder, and means for exerting suction in the cylinder space to procure movement of said element and said cylinder toward said piston and away from said platen, said piston being rockably mounted, thereby allowing said element to assume an outof level position relative to said platen.

2. A press of the class described comprising' a stationary bed or platen, an opposed vertically movable pressure-applying element, a single-acting cylinder attached at its head end to said element, a relatively-stationary piston in said cylinder, means for exerting suction in the cylinder space to procure upward movement of said element and said cylinder toward said piston, and means for bleeding air to said cylinder space, to obtain slow gravitational movement of said element and said cylinder into contact with Work positioned oh said bed or platen.

3. A press of the class described comprising, a stationary bed or platen, an opposed vertically movable pressure-applying element, a single-act ing cylinder attached at its head end to said ele-' ment, a relatively stationary piston disposed within said cylinder, means above'said cylinder After the for pivotally supporting said piston about a substantially horizontal axis, means for exerting suction in the cylinder space to procure movement of said element and said cylinder toward said piston and away from said platen, and means including a constricted conduit for bleeding air slowly to said cylinder space thereby to obtain a slow downward movement of said element and said cylinder under the force of gravity.

4. A press of the class described comprising, a stationary horizontal bed or platen, an opposed vertically movable pressure-applying element, a single-acting open top cylinder having a closed lower portion substantially vertically disposed over said platen with its closed lower portion secured directly to said element, a piston rod supported by its upper end from above said cylinder and with its lower end extending into said cylinder, a piston disposed within said cylinder and pivotally secured to the lower end of said piston rod, means for exerting suction in the cylinder space to procure movement of said element and said cylinder toward said piston and away from said platen, and means including a constricted conduit for bleeding air slowly to said cylinder space thereby to obtain a slow downward movement of said element and said cylinder under the force of gravity.

5. A press of the class described comprising, a frame having a lower horizontally disposed bed or platen and an upper support or suspension means disposed above said platen, cooperating piston and cylindler members arranged between said platen and said suspension means, a pressure-applying element disposed between said platen and said cooperating cylinder and piston members and being rigidly carried by one of said latter two members, means for rockably mounting the other of said two members upon said suspension means thereby allowing said pressure-applying element to assume an out-oflevel position relative to said platen, means for exerting suction in the cylinder space to procure movement of said pressure-applying element away from said platen, and means for slowly bleeding air to said cylinder space to obtain under the force of gravity a slow movement of said pressure-applying element toward said platen.

6. A press of the class described comprising, a frame having a lower horizontally disposed bed or platen and an upper support or suspension means disposed above said platen, cooperating piston and cylinder members arranged between said platen and said suspension means, a pressure-applying element rigidly carried by said cylinder and disposed directly over said platen, a normally endwise immovable piston rod having its upper end secured to said suspension means, a universal joint connecting the lower end of said piston rod to said piston thereby allowing said pressure-applying element to assume an outof-level position relative to said platen, means for exerting suction in the cylinder space to procure movement of said pressure-applying element away from said platen, and means for slowly bleeding air to said cylinder space to obtain under the force of gravity a slow movement of said pressure-applying element toward said platen.

7. A press of the class described comprising, a frame having a lower horizontally disposed bed or platen and an upper support or suspension means disposed above said platen, cooperating piston and cylinder members arranged between said platen and said suspension means, a pressure-applying element rigidly carried by said cylinder and disposed directly over said platen, a normally endwise immovable piston rod having its upper end rockably mounted about a horizontal axis and upon said suspension means, a universal joint connecting the lower end of said piston rod-to said piston thereby allowing said pressure-applying element to assume an out-oflevel position relative to said platen, means for exerting suction in the cylinder space to procure movement of said pressure-applying element away from said platen, and a valve device movable in response to said suction and having therein a constricted conduit for slowly bleeding air to said cylinder space to obtain under the force of gravity a slow movement of said pressureapplying element toward said platen.

VINCENT E. HEYWOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 385,356 Johnson July 3, 1888 678,450 Yeakley July 16, 1901 1,411,788 Kellogg Apr. 4, 1922 1,580,221 Seaholm Apr. 13, 1926 2,332,318 Hughes Oct. 19, 1943 

